Keep full history and download old blobs on demand

Change detection often needs commit history and filenames, not old file contents.

Prompt

Evaluate and apply this CI technique to my repository: Keep full history and download old blobs on demand.

Change detection often needs commit history and filenames, not old file contents.

Read the technique and its source-backed company examples: https://starsling.dev/ci-playbooks/techniques/blobless-history.md

Inspect this repository’s CI workflows, build and test commands, dependencies, and recent run timings. Identify where this technique applies and explain the expected benefit using this repository’s evidence.
Measure a baseline from recent comparable runs: elapsed time, queue time, runner minutes and failures where available. If data is unavailable, say what cannot be measured.
Compare relevant company approaches, checking prerequisites, platform differences and tradeoffs. Rank applicable options by evidence, fit and measurable opportunity; do not present company results as predictions for this repo.
Recommend the smallest safe change, show what checks and fallback paths remain, and ASK ME WHICH CHANGE TO APPROVE BEFORE EDITING ANY FILES.
Only after approval, work on a new feature branch, make one reversible change, and open a reviewable pull request. Never merge or push to a default or protected branch.
Keep required checks, test coverage, deployment and release behavior intact. Validate the change and compare equivalent runs where possible; report limitations and what should be monitored after merge.

View all playbooks

How Mastra used this technique

Read what Mastra changed and follow the original sources.

Keep full history and download old blobs on demand

Seven full-history checkouts gained filter: blob:none while retaining fetch-depth: 0. History stays complete, and old blobs download on demand.

The PR reports transfer falling from 1,572 MB to 189 MB, about 88% fewer bytes. Source

Use it when: Checkout transfer dominates jobs that compare names or trees across commits.
Before applying it: Lazy blob reads still need network access and appropriate credentials.

How Mastra used this technique

Keep full history and download old blobs on demand

Related techniques

Fetch only the repository history a job needs

Serve checkouts from pre-warmed repository clones

Bake stable dependencies into runner images

Company Playbooks

Related guides

Filter workflows by changed files

Cancel superseded CI runs